Photographic enlarging apparatus



sept. 6, .1927. 1,641,346

R. E. MEDER PHOTO'GRAPHIC ENLARQING APPARATUS Filed Mayza, 1926' 2 sheets-sheet 2 l Mfr/@lm ATTORNEYS. y

i Vard. 10.1`

. Patented Sepa-"6, 192'?,

UNITED. ASTA rnofroemuic summum APPARATUS.'

appunti many as, im.' semi m. 112,233. l

This invention relates to -improvements in hoto aphic enlarging apparatus.

e o ject -o invention is to provide greater accuracy in the focal adjustments; to provide automatic means for precisely varying the rate of focal adjustment in. ac' cordance with the' requirements imposed by the distance between thenegative and the screen inany given adjustmentfto provide convenient means for manipulation and, in general, to devise a simple, inexpensiveand eicient apparatus.

' In the drawings: Figure 1 .is an elevation of an` enlarging lap ar'atus embodying my invention.

igure 2 is a p an view of the same; Figure 3 is across sectional view drawn generally on line 3-3 of Figure 1'. i Like partsu are identified by the same reference characters throughout the several views;

A channel shaped standard 10 is mounted upon a suitable ase 11 which extends forwardly and serves .as a tablei and support for the screen. The standard is suitably supported at the' rear side by -ya brace 12 whi h is secured to the base. -The rojector 'carriage comprises Fa frame f bracket shaped cross bar 14;'and arranged to sulport a holder' 15 ffor' the projector. 16.' e rear portion" of the carriage is provided. with vertically elon ated slidemembers 17, the upper ends. o which are connected by a. 'cross b ar 18.v` The lower endl ortions have inturned .il

V I9 which slide upo rear side of the standard 101 The' side arms 13" are .secured tothe innersurfaces of the vertically I elongated slide members- 17 ,bolts or rivets'and are received in channels or guideways 20 formed in 'the outer sur the stand faces .of the side ilan'ges 21 of lle'arone sidev the standard is provided with a vertically vattending rack bar .25, teethv of which,v are mounted u on' a-shaft are journa ed in the lower portions 'of the slide members 17. On one side the end of 50 Vthe shaft projects and is provided with an operating `crank 28,- the rotation of which -causes the pinion 2 6 tovtravel along the rack f bar to raise or'lower the carriage, thereby increasing or diminishing the distance 55 between the projector and the screen holder or'base 11.

aving side arms 13 connected by a the in 'mesliwitha pinion 26 27, the ends of which The projector is provided with a lens holder connected withthebody of the Eojector `'by an" ordinary light excluding llows 3 1, whereby at va ing distances `from -a ne ative moun upon the n'egative holder indicated at 32. Ihe construction of the projector will bein `a c `irdane with ordinary practhe v-lens can be adjusted .tice and further description `or illustrati'onvl is therefore deemed unnecessary.

For the purpcses of the vpresent inven.v tion, the lens holder -30 isiv connected by arms with sleeves 36 mounted to slide-u onguide rods 37 depending from the brac et v arms 14. The sleeves 36 are connected by a cross rod/40 provided withacentral s ol 41 and both sleeves are sup ortedupon t eir respective. guide rodsv 37 liiy' a bell crank having aforwardl-y projectin arm 42 upon which the s ool 41 rests. 'ie bell crank is fulcrume at 44 to forwardly projecting ears 45 on a rackbar 46, the teeth of which mesh with a pinion `47 The rack bar 46 with its projecting ears 45 and arm -42 constitutes an auxiliary carrier adapted to slide along the inner' bar 48 associated with `the stan ard in spaced relation thereto.- Pinion 47 isof'less diameter than the pinion '26 and therefore when thelatter travels downwardly along the rack bar 25, its rotary movement" will be transmitted to v the pinion 47' to feed 'rack 'ba-r 46 downwardly at a.'

more rapid speed but with the increase proportioned' to the relative diameters' of the im` 4`gear wheel and pinion, respectively, thereby exten the bellows 31 andincreasing the distance tween the lens andthenegative in an inverse ratio to the decreasiiigdis- I tance .between the project-'or and -the .screen holder. vThe rate oi extension as-thus determined 'is constant and the pinionmay 'be l I of such sizer as'to extend the 'distance be'- 'tweenthe lens andthe negative as nearly 'in accordance.4 withjthe'requirements as is possible to be done -with a uniform vrate of extension'. compensating adjustment may then be made vby means of the cam guide now to be described. l

-icrum ivot 44m effect' .an exact adjustlcoguide-member 52,. the bearing surl which'has a contour calculatedto swing the bell crank' upon its v ment of t e lens. with reference to the nega- 106 ectng arm 50 provided with an anti-fri n ciated with the rack holder modified by the movement of the bell crank as directed by said cam surface. l

5. Photographie A enlarging apparatus,

comprising the combmation with a screen4 a standard mounted therewith a rack bar, a projector supporting carriage mounted for sliding movement along the standard and provided with a pinion operatively associated with the `rack bar, another pinion adapted to be driven by the lirst mentioned pinion, a lens holder carrier provided with a rack barin mesh with said second pinion, a cam track extending alongthe path of the carrier, and a lever pivotally connected with the carrier and having one arm adapted to be guidedby said Vcam track and another arm connected with the lens holder.

6. Photographic enlarging apparatus, comprising the combination with a screen supporting base, a standard mounted thereon and provided with a rack bar, aprojector supporting carriag mounted for slidin movement along t e standard and provi ed with a pinion operatively assobar, a guide rod supported from said carriage and having a sleeve mounted to slide thereon, a lens holder connected with said sleeve, a lever having one arm in said sleeve and a uiding cam in the path of another arm o said lever for progressively tilting the lever to maintain the lens holder at a proper focusing point during movements of the carriage, an independently movable member mounted upon the carriage in fulcrum bearing relation to said lever, and means for actuating relatively to the carriage and tion of carriage movement. I

7. In a photographic enlarging apparatus, the combination with a projector prosupporting base, 'on and provided in the direcvided with an adjustable lens holder, a pro-I jector supporting carriage, a lens holder positioning member supported from the carriage, means connected with the carriage for operating said ositioning member at a greater speed de itely proportional to the carriage movement and in the same direction, and associated means for transmitting a progressively varying movement to Ehe lens holder from said positioning mem- 8. Photographic l enlarging apparatus actuating relation to said member comprising the combination with a-support, of a projector carriage movabl mounted thereon, an auxiliary lens hol er carrier, means for actuating the same along said support at a constant speed greater than that 'of the projector carriage, a lens holder movably supported from the auxiliary car'- rier, and means motion tthe lens holder,- supplemental to the rate of travel of the auxiliary carrier.

9. Photographic enlarging comprising the Icombination with a support provided with a trackway, of a projector carriage movoably nounted thereon, a projector connected with the carriage and provided with a relatively movable lens holder, another trackway connected with said support, an auxiliary lens holder carrier movably mounted thereon, means for actuating the auxiliary carrier along its trackway at a constant speed dilerent from" that of the projector carriage, and means associated with the lens holder carrier and its trackway for imparting a progressively variable motion to the lens holder to relatively refor impartingaV-variablewi apparatus l tard it during one portion of its carrier movement and accelerating it during the other portion 'of such movement.

10. Photographic enlarging apparatus comprising the combination with a su porting standard, a projector carriage to travel along said standard, a projector connected with the carriage and provided with a relatively movable lens holder, a lens holder carrier independently movable along said standard, motion transmitting connections for actuating the carriage and carrier at different speeds, and cam` actuated motion varying connections between thev carrier and lens holder for modifying the fmovement of the lens holder with reference to thecarrier movement.

11. In a photographic enlarging apparatus, the combination with a projector carriage, of a projector connected therewith and provided with relatively movable lens holder, a lens holder carrier, actuating confnections for moving the carriage and carrier at dilerent speeds, mechanism for transmitting motion from the carrier to the lens holder in a progressively varying proportion to the movements di? the carriage and carrier.

ROBERT E. MEDER.

and speed varying apted Sept. 6, 1927' H, E, NORVIEL ELECTRIC SWITCHv Filed Jan. 20, 1926 

